The present invention relates to a process of the production of bisphenol compounds, which are useful as raw materials of thermoplastic polymers, surface-active agents and stabilizers.
With respect to the process of producing a bisphenol compound, German Patent No. 2,534,558 and JP 58-13528 A (Tokkaisho) each disclose a process in which an .alpha., .alpha."-dihydroxydiisopropylbenzene or a diisopropenylbenzene is reacted with a phenol in the presence of an acidic catalyst such as an ion exchange resin.
In these processes, however, there is a problem that the isolation yield of a bisphenol compound, the intended product, from a reaction mixture is low. This is because an acid, isolated from an ion exchange resin in the reaction, generates a high order adduct of a bisphenol compound when the reaction mixture is heated to remove phenol after the reaction. To solve the problem, JP 8-13770 B (Tokkohei) discloses a process in which excess phenol is distilled off from the reaction mixture containing a bisphenol compound after neutralization by adding a base such as disodium hydrogen phosphate. Then, the resulting mixture is washed with water after the removal of phenol. The bisphenol compound is isolated through crystallization and drying.
This process prevents the production of high order adducts of bisphenol compound but needs inorganic base aqueous solutions for neutralization when bisphenol compounds are isolated from the reaction mixture and purified as the intended products. Moreover, there is a problem in that waste water that contains phenol is generated inevitably and its treatment costs are very high.
JP 5-44932 B (Tokkohei) discloses a process in which a small amount of hydrogen chloride remaining in bisphenol A is removed with anion exchange resins that have pyridyl groups and excellent thermal stability at temperatures higher than 100.degree. C. The gazette does not disclose bisphenol M that is produced according to the present invention, and discloses that basic ion exchange resins having secondary or tertiary amines as exchange groups cannot be used in the production of bisphenol A.